Dear community,
Is it possible to deploy a switch with NNI interfaces where a different S-tag Ethertype
is used on different ports? I mean, Cisco's Q-in-Q on the one port (Ethertype 0x8100)
and IEEE dot1ad on the other (Ethertype 0x88a8).
The switch is supposed to switch the traffic between the ports, based on the S-Vlan
only. There are no UNI ports (popping/pushing of S-Vlan headers).
The switching may be either via conventional bridging or via
EVC. For the first switching method, I think it should be possible
on ME3400E or on Cat6k.
* Cat6k : using trunk ports with 'switchport dot1q ethertype 8100' (default) and
'switchport dot1q ethertype 88a8' respectively
* ME3400E : using trunk ports with 'ethernet dot1ad nni' configured, and without
that configuration
For ME3400E there is an explicit warning not to do this for
common Vlans (this is precisely what is the intention here),
does anybody understand why? What I want is very simple,
no UNI's on this switch and not any L2 protocol tunneling.
For the second method (EVC), I don't have much hope for the platforms that
I looked into (Cat6k-Sup2T and ME3600X). It is nowhere documented which
outer Ethertype is used, but I assume that they support only 0x88a8 on Cat6k and
only 0x8100 on ME3600X. Can anybody confirm that?
IOS syntax on Cat6k-Sup2T (service mode)
enapsulation dot1q 22-44
rewrite ingress tag push dot1ad 10 symmetric
IOS syntax on ME3600X (config manual mentions 'Cisco QinQ Ethertype for S-tags')
rewrite ingress tag push dot1q ...
Ideally we can also do Vlan translation of the S-Vlans. Currently I use a Cat4k (Sup7) which
does that nicely, but the Cat4k seems to only support only (I would be glad if somebody can
correct me here...). EVC seems promising, but I haven't deployed it anywhere.
Many questions here... thanks in advance for the support.
Patrick De Muynck
Space Hellas - Athens - Greece
CCIE 8282
